Power management and monitoring for storage devices

ABSTRACT

In one embodiment, a command for a storage device may be received, wherein the command comprises a plurality of stages. Power for the plurality of stages of the command may be dynamically allocated, wherein power for a first stage of the command is allocated first, and power for each remaining stage of the command is allocated after a preceding stage is performed.

FIELD

The present disclosure relates in general to the field of computersystems, and more specifically, to power management and monitoring forstorage devices.

BACKGROUND

A computer system may include a storage device for storing informationassociated with the computer system. For example, the computer systemmay include a processor, and the processor may execute software thatutilizes the storage device, such as an operating system and/or othersoftware applications. The software may request various operationsinvolving the storage device, such as reading and writing data. Eachoperation performed by the storage device may require varying levels ofpower. In addition, the storage device may have a limited or fixedsupply of available power.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a block diagram of a computer system with one or morestorage devices in accordance with certain embodiments.

FIG. 2 illustrates an example embodiment of a storage device withmulti-stage power management.

FIG. 3A illustrates example operations performed by a storage devicewith single-stage power management.

FIG. 3B illustrates example operations performed by a storage devicewith multi-stage power management.

FIG. 4 illustrates a flow diagram for an example embodiment ofmulti-stage power management for a storage device.

FIG. 5 illustrates an example embodiment of a storage device withdevice-aware power monitoring.

FIG. 6 illustrates example command sequences and system events for astorage device.

FIG. 7 illustrates a flow diagram for an example embodiment ofdevice-aware power monitoring for a storage device.

Like reference numbers and designations in the various drawings indicatelike elements.

DETAILED DESCRIPTION

Although the drawings depict particular systems, components, andembodiments, the concepts of various embodiments are applicable to anysuitable storage devices, processors, circuits, computer systems, andother devices or components. Examples of devices in which teachings ofthe present disclosure may be used include desktop computer systems,server computer systems, storage systems, handheld devices, tablets,other thin notebooks, system on a chip (SoC) devices, and embeddedcomponents. Some examples of handheld devices include cellular phones,digital cameras, personal digital assistants (PDAs), and handheld PCs.Embedded components may include microcontrollers, application specificintegrated circuits (ASIC), digital signal processors (DSP), memory andstorage devices, systems on a chip, network computers (NetPC), set-topboxes, network hubs, wide area network (WAN) switches, or any othercomponent that can perform the functions and operations taught below.Various embodiments of the present disclosure may be used in anysuitable computing environment, such as a personal computer, a server, amainframe, a cloud computing service provider infrastructure, adatacenter, a communications service provider infrastructure (e.g., oneor more portions of an Evolved Packet Core), or other environmentcomprising a group of computing devices.

FIG. 1 illustrates a block diagram of a computer system 100 with one ormore storage devices 120. In the illustrated embodiment, system 100includes a central processing unit (CPU) 102 coupled to main memory 104,a plurality of storage devices 120A-C, and a power supply 150 forpowering the system and its associated components.

During operation, the CPU 102 may request that data be read and/orwritten by the storage devices 120, and the storage devices 120 mayperform the requisite operations in response. Storage devices 120,however, may be required to operate within a certain power envelope,such as the power envelope provided to a storage device 120 by its hostsystem 100. Thus, a storage device 120 may be required to manage itsactive power to ensure that its operations are executed withoutexceeding the available power envelope. For example, a solid-state drivemay perform various read, write, and erase operations on its underlyingmemory (e.g., NAND memory), and thus the solid-state drive may track theoverall power budget and allocate power for those operations, as needed.

Solid-state drives can allocate and release power in a single-stage foreach operation that is performed. For example, solid-state drives couldallocate power once at the beginning of an operation and then releasethat power when the operation completes. However, the operationsperformed by a solid-state drive (e.g., read and write operations onNAND memory) may include multiple phases that each require varyinglevels of power, and the entire amount of power allocated for anoperation may not be needed for all stages of the operation.Accordingly, a storage device that uses single-stage power allocationmay manage power inefficiently, which may lead to lower performance.

As described throughout this disclosure, multi-stage power managementmay be used to manage power more efficiently for a storage device 120.Multi-stage power management is a power allocation scheme that mayallocate power dynamically or separately for each stage of an operation.For example, read and write operations for NAND memory of a solid-statedrive may include multiple stages. A read operation may include a firststage that reads data from NAND memory, and a second stage that outputsthe data. A write (or program) operation may include a first stage thatobtains input data, and a second stage that writes the data to NANDmemory. In certain embodiments, different levels of power may beallocated for these various stages of read and write operations for NANDmemory. In addition, in certain embodiments, power can be requested andallocated in a manner that avoids and/or minimizes any deadlock whenhigh volumes of operations are being performed in parallel. For example,if multiple pending operations have completed their first stage and arewaiting for an increased power allocation for their second stage, but nopower is currently available, then those operations could be deadlockedif they are all waiting for additional power to be allocated withoutreleasing their current allocation of power. As described throughoutthis disclosure, however, deadlock may be avoided through various rulesand policies for allocating power.

Multi-stage power management may be particularly beneficial for storagedevices that connect to their host systems using M.2 interfaces. M.2 isan interface specification for mounting computer expansion cards (e.g.,solid-state drives) with a flexible physical specification that supportsdifferent module widths and lengths. M.2 has a smaller and more flexiblephysical specification and other advanced interfacing features thatrender it particularly suitable in small and/or space-constraineddevices, such as all-in-one desktops, laptops, tablets, and other mobileor portable devices. As a result, M.2 interfaces are often used inpower-constrained devices. Accordingly, multi-stage power management maybe particularly beneficial for storage devices with M.2 interfaces,where the active power available to a storage device 120 is low.

As an example, on a 2 terabyte (TB) solid-state drive with an M.2interface, 6 NAND channels, and a 6 watt (W) power envelope,single-stage power allocation methods may result in approximately 425milliwatts (mW) less power available for write operations, due toallocating power for read operations that must be sufficient for allstages of a read operation. This translates to approximately 170megabytes (MB) of lost write bandwidth if single-stage power allocationis used, which is regained when using multi-stage power allocation. Thisgain in write bandwidth is approximately doubled for a solid-state driveof the same density but with 12 NAND channels and an 8 W power envelope.

In addition, as described throughout this disclosure, device-aware powermonitoring may be used to accurately monitor and report the power usageof a storage device 120, and throttle the power usage of the storagedevice 120 when appropriate. Throttling the power usage of the storagedevice, for example, may involve regulating or adjusting the availablepower in order to lower the overall power usage of the storage device.The components of storage devices 120 that contribute the most to theaverage power consumption may vary for different workloads andoperations. For example, when high capacity storage devices 120 performoperations to read and write data, those operations include units ofwork that may be performed in parallel, singular and sequentially, oranywhere between those extremes. Moreover, the various types of workunits each perform unique functions and consume varying levels of power.For example, at a given time, the workload of a storage device 120 couldinclude the following types of operations and/or work units: 10 memoryreads, 5 memory programs (i.e., writes), 8 data transfer operations, 2memory erases, and 1 activation of an error correction engine. Theoverall average power of the storage device 120 depends on the numberand type of operations and associated work units that are performed.

Storage devices are often power constrained (e.g., solid-state drivesand other non-volatile storage devices) and some may be targeted formarkets that are trending towards low-cost and low-power systems.Accordingly, some storage devices may monitor and regulate their powerusage. For example, a storage device could monitor the power andperformance associated with storage related operations (e.g., operationsthat involve storage access), without tracking the dynamic power usageof other non-storage related operations and the device as a whole (whichtypically accounts for approximately 25-50% of the overall power of astorage device). That type of limited power monitoring could be used toapproximate the average power of a storage device, for example, usingthe actual power monitored for the storage related operations, alongwith a static assumption of the worst-case workload for the other typesof operations that are not monitored (e.g., in lieu of actuallymonitoring the power for those other non-storage related operations).That limited power monitoring approach, however, would not accuratelytrack the average power of a storage device, particularly when thestorage device is not operating at the static worst-case assumption usedto approximate power usage for the non-storage related operations. Theinaccuracy of that limited power monitoring approach leads to thepotential for overly aggressive power throttling, which in turn reducesthe performance of storage devices, and also hinders them from reportingaverage power statistics that are accurate to within +/−1 watt (W), asrequired by industry specifications. In addition, that limited powermonitoring approach does not enable a storage device to be aware of orreport the dynamically changing workload for any non-storage relatedoperations, such as input/output (I/O) operations, system events (e.g.,error-correction, encryption), and any other operations that do notinvolve storage access.

As described throughout this disclosure, device-aware power monitoringmay be used to accurately monitor and report the power usage of storagedevices 120, and throttle the power usage of storage devices 120 whenappropriate. Device-aware power monitoring, for example, may enablemonitoring of the dynamically changing workload and power for all typesof operations and work units of a storage device 120. For example, asolid-state drive may include an interface, a controller, and a mediaarray for storing data (e.g., an array of memory cells, such asNAND-based memory cells), among other components. Device-aware powermonitoring may be used to track all operations performed by the variouscomponents of the solid-state drive, including the number of media arrayread operations, media array write operations, media array eraseoperations, data transfer operations (e.g., I/O operations), and systemevents or other non-media operations. Thus, device-aware powermonitoring enables accurate tracking of the full system power of storagedevices 120 by monitoring all workload types and amounts, which improvesthe accuracy of the statistical reporting to end users, and allowsthrottling to be selectively performed only when necessary. In addition,device-aware power monitoring enables accurate power monitoring withoutusing a static worst case assumption to calculate power usage, andwithout adding costly external power sensing components.

The power management and monitoring functionality described throughoutthis disclosure provides numerous technical advantages, including moreefficient power management that minimizes deadlock and maximizes theperformance of storage devices 120, such as solid-state drives. This isparticularly beneficial for storage devices 120 with limited power, suchas storage devices that connect to power-constrained host systems usingM.2 interfaces, where the operations performed by the storage device maybe limited by the available power. In addition, this solution is alsoparticularly beneficial for storage devices 120 that use differentlevels of power for various stages of an operation, such as solid-statedrives of high densities where the NAND channel I/O power is greaterthan the NAND array power. Moreover, device-aware power monitoringenables the full power of storage devices to be accurately tracked andreported, allowing throttling to be performed more selectively to avoiddegradations in performance from overly aggressive throttling, andachieving cost-savings from providing accurate power monitoring withoutcostly external power sensing components.

The power management and monitoring functionality described throughoutthis disclosure may be implemented, for example, by storage devices 120of system 100. In the illustrated embodiment, system 100 includes CPU102, main memory 104, storage devices 120A-C, and power supply 150, asdescribed further below.

CPU 102 comprises a processor 108, such as a microprocessor, an embeddedprocessor, a digital signal processor (DSP), a network processor, ahandheld processor, an application processor, a co-processor, a systemon a chip (SoC), or other device to execute code (i.e., softwareinstructions). Processor 108, in the illustrated embodiment, includestwo processing elements (cores 114A and 114B in the illustratedembodiment), which may include asymmetric processing elements orsymmetric processing elements. However, a processor may include anynumber of processing elements that may be symmetric or asymmetric.

In one embodiment, a processing element refers to hardware or logic tosupport a software thread. Examples of hardware processing elementsinclude: a thread unit, a thread slot, a thread, a process unit, acontext, a context unit, a logical processor, a hardware thread, a core,and/or any other element, which is capable of holding a state for aprocessor, such as an execution state or architectural state. In otherwords, a processing element, in one embodiment, refers to any hardwarecapable of being independently associated with code, such as a softwarethread, operating system, application, or other code. A physicalprocessor (or processor socket) typically refers to an integratedcircuit, which potentially includes any number of other processingelements, such as cores or hardware threads.

A core 114 may refer to logic located on an integrated circuit capableof maintaining an independent architectural state, wherein eachindependently maintained architectural state is associated with at leastsome dedicated execution resources. A hardware thread may refer to anylogic located on an integrated circuit capable of maintaining anindependent architectural state, wherein the independently maintainedarchitectural states share access to execution resources. As can beseen, when certain resources are shared and others are dedicated to anarchitectural state, the line between the nomenclature of a hardwarethread and core overlaps. Yet, a core and a hardware thread are oftenviewed by an operating system as individual logical processors, wherethe operating system is able to individually schedule operations on eachlogical processor.

In various embodiments, the processing elements may also include one ormore arithmetic logic units (ALUs), floating point units (FPUs), caches,instruction pipelines, interrupt handling hardware, registers, or otherhardware to facilitate the operations of the processing elements.

I/O controller 110 is a controller that includes logic to facilitatecommunication between CPU 102 and I/O devices (e.g., storage devices120). I/O controller 110 may be, for example, an internal I/O controllerintegrated with CPU 102, an external I/O controller separate from CPU102, and/or a combination of internal and external I/O controllers. I/Ocontroller 110 may interact with any I/O device capable of transferringdata to, and/or receiving data from, an electronic system such as CPU102. I/O devices may include, for example, data storage devices (e.g.,storage devices 120), wireless transceivers, network interfaces, networkprocessors, audio/video (A/V) devices, monitors, mice, keyboards,printers, scanners, and/or any other suitable input or output device. Inthe illustrated embodiment, I/O controller 110 may facilitatecommunication between CPU 102 and storage devices 120. For example, CPU102 may use I/O controller 110 to read data from a storage device 120 orwrite data to a storage device 120 (e.g., by issuing commands to readand write data at particular addresses or locations on the storagedevice 120).

An I/O device may communicate with the I/O controller 110 of the CPU 102using any suitable interface and/or signaling protocol, such as M.2interfaces, peripheral component interconnect (PCI), PCI Express (PCIe),Universal Serial Bus (USB), Serial Attached SCSI (SAS), Serial ATA(SATA), Fibre Channel (FC), IEEE 802.3, IEEE 802.11, logical deviceinterface specifications such as Non-Volatile Memory Express (NVMe)(e.g., as described by specification(s) available atwww.nvmexpress.org/specifications/) or the Advanced Host ControllerInterface (AHCI) (e.g., the Serial ATA AHCI Specification, Rev. 1.3.1available athttp://www.intel.com/content/www/us/en/io/serial-ata/serial-ata-ahci-spec-rev1-3-1.html),or any other current or future interface or signaling protocol. Invarious embodiments, I/O devices coupled to the I/O controller 110 maybe located off-chip (i.e., not on the same chip as CPU 102) or may beintegrated on the same chip as the CPU 102.

CPU memory controller 112 may be a controller that includes logic formanaging the flow of data going to and from main memory 104 of computingsystem 100. Main memory 104 may include any of a wide variety ofmemories, including but not limited to, random access memory (RAM)(e.g., dynamic random access memory (DRAM), synchronous dynamic randomaccess memory (SDRAM), static random access memory (SRAM)), read onlymemory (ROM), logic blocks of a field programmable gate array (FPGA),erasable programmable read only memory (EPROM), electrically erasableprogrammable ROM (EEPROM), and/or any suitable combination of theforegoing. CPU memory controller 112 may include logic to read from mainmemory 104, write to main memory 104, and/or request other operationsfor main memory 104. In some embodiments, CPU memory controller 112 maybe implemented on the same chip as CPU 102, whereas in otherembodiments, CPU memory controller 112 may be implemented on a differentchip than that of CPU 102.

Power supply 150 may include any component used to supply power tosystem 100 and/or its associated components, such as alternating current(AC) power sources (e.g., electrical outlets) and direct current (DC)power sources (e.g., batteries). Power supply 150 may be coupled,directly or indirectly, to CPU 102 and/or processor 108, storage devices120, and/or any other component of system 100.

Storage devices 120A-C may include any suitable devices for storingdata. For example, in some embodiments, a storage device 120 may be adevice with non-volatile storage for persistently storing data, such asa solid-state drive, flash-based memory device, and/or hard disk drive.Storage devices 120 may be used, for example, to store data associatedwith files and programs of computer system 100 (e.g., user files, codefor software applications). In some embodiments, a storage device 120may be dedicated to a particular CPU 102 and/or shared with other CPUsor devices.

Storage devices 120 may include any type or combination of non-volatileand/or volatile storage. Non-volatile storage is a storage medium thatretains data even without power. Non-limiting examples of non-volatilestorage may include any or a combination of: solid-state storage (e.g.,any form of persistent flash memory, including planar or threedimensional (3D) NAND flash memory or NOR flash memory), 3D crosspoint(or 3D XPoint) memory, storage devices that use chalcogenide phasechange material (e.g., chalcogenide glass), byte addressablenon-volatile memory devices, ferroelectric memory,silicon-oxide-nitride-oxide-silicon (SONOS) memory, polymer memory(e.g., ferroelectric polymer memory), ferroelectric transistor randomaccess memory (Fe-TRAM) ovonic memory, nanowire memory, electricallyerasable programmable read-only memory (EEPROM), and/or various othertypes of non-volatile random access memories (RAM). In particularembodiments, a storage device 120 with non-volatile storage may complywith one or more standards promulgated by the Joint Electron DeviceEngineering Council (JEDEC), such as JESD218, JESD219, JESD220-1,JESD223B, JESD223-1, or other suitable standard (the JEDEC standardscited herein are available at www.jedec.org). Storage devices 120 mayalso include any type or combination of volatile storage 122. Volatilestorage is a storage medium that requires power to retain data. Examplesof volatile storage may include various types of random access memory(RAM), such as dynamic random access memory (DRAM), synchronous dynamicrandom access memory (SDRAM), and static random access memory (SRAM). Inparticular embodiments, storage devices 120 with DRAM may comply with astandard promulgated by JEDEC, such as JESD79F for Double Data Rate(DDR) SDRAM, JESD79-2F for DDR2 SDRAM, JESD79-3F for DDR3 SDRAM, orJESD79-4A for DDR4 SDRAM (these standards are available atwww.jedec.org). Such standards (and similar standards) may be referredto as Double Data Rate (DDR) based standards, and communicationinterfaces of storage devices 120 that implement such standards may bereferred to as DDR-based interfaces.

In the illustrated embodiment, storage device 120A includes data storage122, storage controller 124, and power controller 126. Data storage 122comprises a plurality of storage modules 123A-D. A storage module 123may be any component or mechanism capable of storing data, including anytype or combination of non-volatile and/or volatile storage. Forexample, in some embodiments, storage modules 123 may include: memorychips, dies, and modules (e.g., flash-based memory chips, RAM chips,dual in-line memory modules (DIMM)); memory cells on a chip, die, ormodule (e.g., NAND, NOR, and other flash-based memory cells, RAM memorycells); and/or magnetic and optical storage mediums (e.g., disks orplatters of a hard disk drive). In various embodiments, data storage 122may include any suitable number, type, and arrangement of storagemodules 123. For example, a storage module 123 could be a flash-basedmemory chip with a plurality of memory cells that are each operable tostore one or more bits. In various embodiments, storage modules 123(and/or the underlying memory cells) may be arranged or logicallygrouped into columns and rows, three-dimensional structures, channels,banks, blocks, pages (e.g., wherein a page is a subset of a block),frames, bytes, file segments, cylinders, tracks, sectors, or any othersuitable arrangements or groupings.

Storage devices 120 may comprise any suitable type of storage and arenot limited to any particular storage technology, speed, and/or formfactor. Moreover, computer system 100 may include multiple differenttypes of storage devices 120. For example, in some embodiments, computersystem 100 may include tiered storage, such as a first tier of solidstate drives and a second tier of hard disk drives. Storage devices 120may communicate with I/O controller 110 using any suitable communicationprotocol, such as a DDR-based protocol, PCI, PCIe, USB, SAS, SATA, FC,System Management Bus (SMBus), or other suitable protocol. Storagedevices 120 may also include a communication interface (e.g., an M.2interface) to communicate with I/O controller 110 in accordance with anysuitable logical device interface specification, such as NVMe, AHCI, orany other suitable specification. In particular embodiments, storagedevice 120 may comprise multiple communication interfaces that eachcommunicate using a separate protocol with I/O controller 110.

Storage controller 124 may include logic to receive requests from CPU102 (e.g., via I/O controller 110), cause the requests to be carried outwith respect to data storage 122, and provide data associated with therequests to CPU 102 (e.g., via I/O controller 110). Storage controller124 can be implemented on the same chip, board, or device as datastorage 122 or on a different chip, board, or device. For example, insome embodiments, storage controller 124 may be a centralized controllerthat manages storage operations for multiple different storage devices120 and/or data storages 122 (which may be of the same type or ofdifferent types).

Power controller 126 may include logic to manage power for the storagedevice 120. In the illustrated embodiment, the power controller 126 isshown as being part of the storage controller 124 of the storage device120, although in certain embodiments the power controller 126 may be aseparate component from (but communicatively coupled to) the storagecontroller 124. For example, in various embodiments, the powercontroller 126 may be integrated on the same chip as the storagecontroller 124 or on a different chip. In some embodiments, storagecontroller 124 and/or power controller 126 may implement the powermanagement and monitoring functionality described throughout thisdisclosure.

In various embodiments, storage devices 120 may also includeerror-correction functionality. For example, in some embodiments, anerror-correction engine may be included. The error-correction engine maybe operable to detect and/or correct errors encountered in data duringoperation of the storage device 120. In various embodiments, theerror-correction engine may be included within the storage controller124 or may be communicably coupled to the storage controller 124. Forexample, in some embodiments, the error-correction engine may beintegrated on the same chip as the storage controller 124 or may beimplemented on a different chip.

In various embodiments, storage devices 120 may also include encryptionfunctionality. For example, in some embodiments, an encryption enginemay be included. The encryption engine may be used to encrypt anddecrypt data stored by the storage device. For example, the encryptionengine may be operable to receive data associated with a write command,encrypt the data, and provide the encrypted data to be written to datastorage 122. In some embodiments, the encrypted data may be the samelength as the original data in order to simplify the logical to physicalmappings of data. The encryption engine may also be operable to receiveencrypted data retrieved from data storage 122, decrypt the data intoits original form (e.g., as originally received from CPU 102), andprovide the decrypted data for transmission to CPU 102 or anotherrequesting entity (e.g., in response to a command to read data). Invarious embodiments, the encryption engine may be included within thestorage controller 124 or may be communicably coupled to the storagecontroller 124. For example, in some embodiments, the encryption enginemay be integrated on the same chip as the storage controller 124 or maybe implemented on a different chip. In certain embodiments, thecomputing host may not need to manage encryption and decryption of datastored on storage device 120 when the encryption functionality ismanaged by storage device 120.

In some embodiments, all or some of the elements of system 100 may beresident on (or coupled to) the same circuit board (e.g., amotherboard). In various embodiments, any suitable partitioning betweenthe elements may exist. For example, the illustrated elements of CPU 102may be located on a single die or package (i.e., on-chip) or any of theelements of CPU 102 may be located off-chip. Similarly, the illustratedelements of storage device 120A may be located on a single chip or onmultiple chips. In various embodiments, a storage device 120 and itscomputing host (e.g., CPU 102) may be located on the same circuit boardor on the same device, while in other embodiments the storage device 120and the computing host may be located on different circuit boards ordevices.

The components of system 100 may be coupled together in any suitablemanner. For example, a bus may couple any of the components together. Abus may include any known interconnect, such as a multi-drop bus, a meshinterconnect, a ring interconnect, a point-to-point interconnect, aserial interconnect, a parallel bus, a coherent (e.g. cache coherent)bus, a layered protocol architecture, a differential bus, and a Gunningtransceiver logic (GTL) bus. In various embodiments an integrated I/Osubsystem includes point-to-point multiplexing logic between variouscomponents of system 100, such as cores 114, one or more CPU memorycontrollers 112, I/O controller 110, integrated I/O devices, directmemory access (DMA) logic (not shown), etc. In various embodiments,components of computer system 100 may be coupled together through one ormore networks comprising any number of intervening network nodes, suchas routers, switches, or other computing devices. For example, acomputing host (e.g., CPU 102) and the storage device 120 may becommunicatively coupled through a network. Although not depicted in theillustrated embodiment, system 100 may include a display to output dataprovided by CPU 102, a network interface to communicate over a network,and/or any other peripherals, interfaces, or components. In someembodiments, these components may be communicatively coupled to CPU 102.

FIG. 2 illustrates an example embodiment of a storage device 200 withmulti-stage power management. In some embodiments, storage device 200may be used to implement the storage devices 120 of FIG. 1.

Storage device 200 may be, for example, a solid state drive. In theillustrated embodiment, storage device 200 includes a data storage 222and a storage controller 224. The data storage 222 includes NAND dies223 and storage buses 240. However, while the illustrated embodimentincludes NAND dies 223, other embodiments may include any other type orcombination of non-volatile memory or storage. The storage controller224 includes NAND channels 225, power management controller 226, andpower management interfaces 231-233. In some embodiments, the storagecontroller 224 may be implemented using an application specificintegrated circuit (ASIC), such as a solid-state drive controller thatis implemented in the hardware and/or firmware of an ASIC.

The NAND dies 223 are memory chips that store data using NAND-basedmemory cells. The NAND dies 223 may be connected to the storagecontroller 224 using storage buses 240. In the illustrated embodiment,the NAND dies 223 are grouped into multiple NAND channels 225, and eachchannel 225 may be used to interact with its associated NAND dies 223using the storage bus 240 for that channel. For example, the illustratedembodiment includes NAND channels 1-N (225A-225C), and each channel 225is connected to a group of NAND dies (223A-223C) using a storage bus(240A-240C). The NAND channels 225 may allow the controller 224 tointeract with multiple NAND dies 223 simultaneously.

The NAND channels 225 may be connected to a power management controller226 that manages power for the storage device 200. In the illustratedembodiment, each NAND channel 225 is connected to the power managementcontroller 226 using three interfaces: an interface 231 for requestingpower credits for the first stage of an operation; an interface 232 forrequesting power credits for the second stage of an operation; and aninterface 233 for releasing power credits. Each interface 231-233 may beimplemented using any suitable mechanism for enabling communicationbetween a NAND channel 225 and power management controller 226 (e.g., tosend and receive power credit requests, power credits, power creditreleases, and/or any other power-related requests, commands, andresponses). For example, in some embodiments, each interface 231-233 maybe implemented using a single line or wire, multiple lines or wires, abus, and/or any other mechanism that enables communication between aNAND channel 225 and power management controller 226.

The NAND channels 225 may request power credits from the powermanagement controller 226 before performing read and write operations onthe NAND dies 223. Read and write operations may include multiplestages, including an I/O stage and a media access stage. For example, aNAND die 223 may store data using a media array, which is an array ofNAND-based memory cells. Read and write operations may include one stageto read from or write to the media array of a NAND die 223, and anotherstage to perform I/O. For example, a read operation may include a firststage that reads data from a media array on a NAND die 223, and a secondstage that outputs the data. A write (or program) operation may includea first stage that obtains input data, and a second stage that writesthe data to a media array on a NAND die 223.

Storage devices could use single-stage power management, which allocatesand releases power only once for each read and write operation. However,that single-stage approach may result in inefficient allocations ofpower, as the I/O stage and the media access stage of NAND read andwrite operations have different power profiles. Moreover, because thepower required for the I/O stage is dependent on the number of NAND dies223 connected to each NAND channel 225, it may vary based on the densityof the storage device 220.

Accordingly, storage device 200 uses multi-stage power management toallocate power more efficiently, for example, by dynamically allocatingpower for each stage of an operation. For example, multi-stage powermanagement may allocate different levels of power for each stage of readand write operations. In addition, power can be allocated in a mannerthat avoids and/or minimizes deadlock when high volumes of operationsare being performed in parallel. For example, if multiple pendingoperations have completed their first stage and are waiting for anincreased power allocation for their second stage, but no power iscurrently available, then those operations could be deadlocked if theyare all waiting for additional power to be allocated without releasingtheir current allocation of power. As described throughout thisdisclosure, however, deadlock may be avoided through various rules andpolicies for allocating power.

When using multi-stage power management to perform a command, such as aread or write operation, the command may first be received by storagecontroller 224 and/or by the appropriate NAND channel 225. The NANDchannel 225 may then request a power credit from the power managementcontroller 226 for the first stage of the operation. A power credit, forexample, may be an allocation of power for a particular operation. Oncethe power credit has been provided, the NAND channel 225 (or any othercomponent of storage controller 224) may then initiate performance ofthe first stage of the operation. After the first stage of the operationis performed, the NAND channel 225 may then request a power creditadjustment from the power management controller 226 for the second stageof the operation. Once the power credit adjustment has been provided,the NAND channel 225 (or any other component of storage controller 224)may then initiate performance of the second stage of the operation.After the second stage of the operation is performed, the NAND channel225 may then release the power credit back to the power managementcontroller 226.

Within the storage controller 224, multiple NAND channels 225 can beconcurrently requesting power credits from the power managementcontroller 226. In addition, within a given NAND channel 225, there maybe multiple pending read and write operations that are being allocatedpower credits for a particular stage or are having power creditsreleased. Accordingly, deadlocks can potentially occur due to theconcurrent usage model of multi-stage power management. In order toprevent deadlock from occurring, separate interfaces may be used torequest power credits for each stage of an operation. For example, inthe illustrated embodiment, power credits for the first stage of anoperation are requested using interface 231, power credits for thesecond stage of an operation are requested using interface 232, andpower credits are released for an operation using interface 233. Inaddition, certain rules and policies may be enforced to preventdeadlock.

First, the power credit interfaces (231 and 232) may each support asingle outstanding power credit request from a NAND channel 225 to thepower management controller 226. If a request is pending on a powercredit interface and is stalled waiting for the power managementcontroller 226 to respond, a NAND channel 225 may wait to send any newpower credit requests on that interface until the outstanding request iscompleted by the power management controller 226.

Second, if a NAND channel 225 has stage 1 and stage 2 power credits torequest for various operations, the NAND channel may send the stage 2request on the stage 2 interface (interface 232) before sending thestage 1 request on the stage 1 interface (interface 231).

Third, power credit releases may be sent from a NAND channel 225 to thepower management controller 226 at any time using the power creditrelease interface 233, regardless of whether there are pending powercredit requests on power credit interfaces 231 and 232.

Finally, if stage 1 of an operation completes and that operation isready for a stage 2 power credit adjustment, but another stage 2 requestis already pending on interface 232, the power credit for the recentlycompleted stage 1 may be released entirely instead of requesting a stage2 power credit adjustment, allowing the pending stage 2 request tocomplete using the power that is released. After the pending stage 2request completes, a stage 2 power credit may then be requested for theoperation whose stage 1 power credit was released. For example, if aNAND channel 225 determines that stage 1 of a read operation (i.e., themedia read stage) completes while another stage 2 request is alreadypending on interface 232, the NAND channel may forego the stage 2 powercredit adjustment for the read operation and instead release its stage 1power credit, allowing the pending stage 2 request for the otheroperation to complete. The NAND channel 225 may then request a powercredit for stage 2 of the read operation (i.e., the I/O stage). Thus,rather than adjusting the stage 1 power credit of the read operation forstage 2 when another stage 2 request is already pending, the stage 1power credit is released entirely and a new power credit is subsequentlyrequested for stage 2.

Moreover, in some embodiments, the power management controller 226 mayuse an arbitration scheme to process the pending power credit requestsand releases sent from multiple NAND channels 225. First, beforeprocessing any stage 1 or stage 2 requests, the power managementcontroller 226 may process all pending power credit releases sent usingthe power credit release interfaces 233. Next, the power managementcontroller 226 may process all pending stage 2 power credit requeststhat were sent using the stage 2 request interfaces 232. In someembodiments, the power management controller 226 may use a round-robinarbitration scheme to cycle through each NAND channel 225 and processany pending stage 2 request sent by each NAND channel 225. Next, thepower management controller 226 may process all pending stage 1 powercredit requests that were sent using the stage 1 request interfaces 231.In some embodiments, the power management controller 226 may use around-robin arbitration scheme to cycle through each NAND channel 225and process any pending stage 1 request sent by each NAND channel 225.

FIGS. 3A and 3B illustrate example read and program (write) operationsperformed by a storage device. In FIG. 3A, the example operations areperformed by a storage device with single-stage power management. InFIG. 3B, the same example operations are performed by a storage devicewith multi-stage power management.

FIG. 3A illustrates a read operation 310A and a program (i.e., write)operation 320A using single-stage power management. The read operation310A includes two stages: a first stage 312 to read the NAND array, anda second stage 314 to perform the I/O for the read operation. Usingsingle-stage power management, a power credit is requested 311 for theentire read operation 310A before performing the first stage. The firststage 312 and the second stage 314 of the read operation 310A are thenperformed using the power credit allocated for the read operation. Afterboth stages of the read operation 310A are complete, the power credit isthen released 315 for the read operation. Similarly, the program (orwrite) operation 320A includes two stages: a first stage 322 to performthe I/O for the program operation (i.e., obtain the data to write tomemory), and a second stage 324 to program the data to the NAND array.Using single-stage power management, a power credit is requested 321 forthe entire program operation 320A before performing the first stage. Thefirst stage 322 and the second stage 324 of the program operation 320Aare then performed using the power credit allocated for the programoperation. After both stages of the program operation 320A are complete,the power credit is then released 325 for the program operation.

FIG. 3B illustrates a read operation 310B and a program (i.e., write)operation 320B using multi-stage power management. The read operation310B from FIG. 3B includes the same two stages as the read operation310A from FIG. 3A. However, using multi-stage power management, a powercredit is requested 311 for stage 1 of the read operation 310B. Thefirst stage 312 of the read operation 310B is then performed. After thefirst stage 312 of the read operation 310B is complete, the power creditfor stage 1 is adjusted 313 for stage 2. The second stage 314 of theread operation 310B is then performed. After the second stage 314 of theread operation 310B is complete, the power credit for stage 2 of theread operation is released 315.

Similarly, the program (write) operation 320B from FIG. 3B includes thesame two stages as the program operation 320A from FIG. 3A. However,using multi-stage power management, a power credit is requested 321 forstage 1 of the program operation 320B. The first stage 322 of theprogram operation 320B is then performed. After the first stage 322 ofthe program operation 320B is complete, the power credit for stage 1 isadjusted 323 for stage 2. The second stage 324 of the program operation320B is then performed. After the second stage 324 of the programoperation 320B is complete, the power credit for stage 2 of the programoperation is released 325.

FIG. 4 illustrates a flow diagram 400 for an example embodiment ofmulti-stage power management for a storage device. The flow diagram 400depicts example operations that may be performed by any suitable logicand/or components, including the components described throughout thisdisclosure (e.g., storage devices 120 of FIG. 1, storage device 200 ofFIG. 2, and/or storage device 500 of FIG. 5).

The flow diagram may begin at block 402 by receiving a command for astorage device. The storage device, for example, may be a solid-statedrive with non-volatile memory. The command could be, for example, aread operation or a program (i.e., write) operation. The command, suchas a read operation or a program operation, may include multiple stages.For example, a read operation may include a first stage to read datafrom a NAND array and a second stage to output the data. Similarly, aprogram (i.e., write) operation may include a first stage to obtain datato store in the storage device and a second stage to write the data to aNAND array.

The flow diagram may then proceed to block 404 to allocate power for thefirst stage of the command. In some embodiments, however, power may beallocated for the first stage of the command only after allocating powerfor a second stage of one or more pending commands. The flow diagram maythen proceed to block 406 to perform the first stage of the commandusing the power allocated in block 404.

The flow diagram may then proceed to block 408 to allocate power for thesecond stage of the command. In some embodiments, allocating power forthe second stage may comprise adjusting the power that was allocated forthe first stage. In addition, in some embodiments, separate interfacesmay be used to allocate power for the first stage and the second stageof the command. Finally, in some embodiments, it may be determined thatanother power allocation request is pending for a second stage of adifferent pending command. In those embodiments, the power allocated atblock 404 for the first stage of the current command may be released,and power may then be allocated for the second stage of the otherpending command. Once the second stage of the other command completesand that power is released, power may then be allocated for the secondstage of the current command.

The flow diagram may then proceed to block 410 to perform the secondstage of the command using the power allocated in block 408.

The flow diagram may then proceed to block 412 to release power for thecommand. For example, the power allocated (or adjusted) for the secondstage of the command may be released. In some embodiments, power may bereleased for the command using an interface that is different from theinterface(s) used to allocate power for the command. In someembodiments, power allocated and released for each command and/or otheroperations may also be tracked (e.g., using an accumulator) formonitoring, reporting, and/or throttling purposes.

At this point, the flow diagram may be complete. In some embodiments,however, the flow diagram may restart and/or certain blocks may berepeated. For example, in some embodiments, the flow diagram may restartat block 402 to continue processing commands for the storage device.

The flow diagram described in FIG. 4 is merely representative ofoperations that may occur in particular embodiments. In otherembodiments, additional operations may be performed and/or certainoperations may be omitted. Various embodiments of the present disclosurecontemplate any suitable mechanisms for accomplishing the functionsdescribed herein. Some of the operations illustrated in the flow diagramof FIG. 4 may be repeated, combined, modified, and/or deleted whereappropriate. Additionally, operations may be performed in any suitableorder without departing from the scope of particular embodiments.

FIG. 5 illustrates an example embodiment a storage device 500 withdevice-aware power monitoring. Storage device 500 may be, for example, asolid-state drive with non-volatile memory (NVM) 508. In someembodiments, storage device 500 may be used to implement the storagedevices 120 of FIG. 1.

A storage device could simply monitor and accumulate the total energyused for storage related operations (e.g., media array reads, mediaarray programs, and media array erases) without monitoring and trackingthe energy used for other types of operations or events (e.g., I/Ooperations, error-correction, encryption, and/or other system events).However, that power monitoring approach would be limited, as it wouldonly enable monitoring of the power consumed by the storage or memory ofa storage device (e.g., a media array) rather than the overall storagedevice as a whole, and it would not allow information to be retainedabout the type and quantity of each underlying unit of work performed bya storage device.

Accordingly, storage device 500 may include device-aware powermonitoring that accurately monitors all power used by the storagedevice. Device-aware power monitoring, for example, may enablemonitoring of the type and quantity of each work unit performed by thestorage device 500. In some embodiments, for example, storage device 500may implement an N-energy accumulator that maintains an individualaccumulator for each type of work unit. Accumulating energy separatelyfor each type of work unit enables storage device 500 to monitor andtrack power usage with more granularity than existing storage devices.Moreover, the full power usage of the storage device 500 may beaccurately monitored by accumulating energy for all workload types,including workload types that are not tracked by existing storagedevices (e.g., I/O operations, error-correction, encryption, and/orother system events).

In the illustrated embodiment, storage device 500 includes channels 525,dispatcher 504, power credit pool 506, non-volatile memory 508,power/energy lookup table 510, N-energy accumulator 512, power monitor514, power reporter 516, power regulator 518, and completer 520.

Storage device 500 may perform various operations associated withcommands (e.g., read, program, erase) and/or system events. Each commandsequence or system event may comprise one or more work units 502corresponding to different stages of an operation (as illustrated inFIG. 6). In the illustrated embodiment, the work units 502 associatedwith various operations are being processed by the storage device 500.The work units 502, for example, may be associated withread/program/erase commands from one or more NVM channels 525 of thestorage device 500 (e.g., NAND channels of a NAND-based storage device),or with system events triggered for the storage device 500.

Each work unit 502 may be processed initially by a dispatcher 504 of thestorage device 500. In the illustrated embodiment, for example, workunit X 502 is being processed by dispatcher 504. Dispatcher 504 may uselookup table 510 to look up the quantum of power and/or energy 552required for a particular type of work unit 502. For example, lookuptable 510 may include a table that identifies the corresponding powerand/or energy required for each type of work unit 502.

Dispatcher 504 may then signal the N-energy accumulator 512 toaccumulate the energy units 553 required by the particular work unit502. The N-energy accumulator 512, for example, may include a separateaccumulator 513 for each type of work unit 502 that may be performed bythe storage device 500. The N-energy accumulator 512 may includeaccumulators 513 for work units 502 that involve storage access (e.g.,read, program, erase) and other work units 502 that do not directlyinvolve storage access (e.g., I/O operations, system events). In thismanner, the N-energy accumulator 512 may track the energy consumptionfor each type of work, along with its energy contribution to the entirestorage device 500. For example, dispatcher 504 may notify the N-energyaccumulator 512 that a particular type of work unit is being dispatched,allowing the N-energy accumulator 512 to increment the individualaccumulator 513A-513Z for that work unit by the appropriate quantum ofenergy.

Dispatcher 504 may then request power credits 551 for the work unit 502from the power credit pool 506. The power credit pool 506, for example,may be a quota of power credits used to allocate power for the workunits 502 performed by the storage device 500. After the dispatcher 504obtains a power credit for the current work unit 502, the work unit 502may then be processed using the allocated power. For example, if thework unit 502 requires storage access, then the non-volatile memory 508may be accessed. The non-volatile memory 508 may be, for example, flashmemory, NAND, or any other form of solid-state or non-volatile storage.The work unit 502 may then be passed to the completer 520 to handle anyremaining processing required for the work unit 502 (e.g., input/output(I/O) processing, error-correction). After all processing for the workunit 502 is complete, the completer 520 may then release the powercredit 554 for that work unit 502 back to the power credit pool 506.

A power monitor 514 may be used to periodically check the energy valuesin the N-energy accumulator 512, and calculate the average power usageof the storage device 500 over a given time interval. Because theN-energy accumulator 512 maintains separate accumulators 513 for allwork types, the average power calculated by power monitor 514 measuresthe full power usage of the storage device 500. The power monitor 514may then provide the computed average power to power reporter 516 andpower regulator 518.

Power reporter 516 may track and report power related information (e.g.,average power), statistics, and/or events for the storage device 500.For example, power related information, statistics, and/or events may bereported 555 to a host computing system 522 and/or a user of the hostcomputing system.

Power regulator 518 may be used, for example, to throttle the powerusage of the storage device 500 when appropriate. For example, powerregulator 518 may evaluate the average power calculated by power monitor514, compare the average power to a set target power (e.g., an averagepower usage goal), and perform a real-time calibration 556 of the sizeof the power credit pool 506 in order to achieve the target power.Together, power monitor 514 and power regulator 518 may form aclosed-loop control system.

FIG. 6 illustrates examples 600 of command sequences 610 and systemevents 620 for a storage device. Command sequences 610 and system events620 may be processed, for example, by storage device 500 of FIG. 5.

Command sequences 610 may be, for example, sequences of commandsassociated with read, program, and/or erase operations. System events620 may be, for example, events that are triggered for a storage device,such as an error-correction algorithm. Each command sequence 610 orsystem event 620 may comprise one or more work units 630 correspondingto different stages of a particular command and/or event.

The illustrated examples 600 includes command sequences 1 to N (610-1 to610-N). Command sequence 1 (610-1) includes work unit A (630A) and workunit B (630B). Command sequence 1 may correspond to a read operation,for example, where work unit A reads data from memory, and work unit Bperforms an I/O transfer of the data read from memory. Command sequence2 (610-2) includes work unit C (630C). Command sequence 2 may correspondto an erase operation, for example, where work unit C erases aparticular memory location. Command sequence N (610-N) includes workunit D (630D) and work unit E (630E). Command sequence N may correspondto a program (or write) operation, for example, where work unit Dperforms an I/O operation to obtain the data to write to memory, andwork unit E writes that data to memory.

The illustrated examples 600 also includes system events 1 to N (620-1to 620-N). System event 1 (620-1) includes work unit X (630X). Systemevent 1 may correspond to an error-correction event, for example, wherework unit X performs an error-correction algorithm. System event N(620-N) includes work unit Y (630Y) and work unit Z (630Z). System eventN may correspond to a power reporting event, for example, where workunit Y calculates the average power of the storage device and work unitZ performs an I/O operation to report the average power to a hostcomputing system and/or user.

In some embodiments, the power and/or energy required by each work unitof the example command sequences 610 and system events 620 may bemonitored and/or tracked by a storage device, for example, as describedin connection with storage device 500 of FIG. 5.

FIG. 7 illustrates a flow diagram 700 for an example embodiment ofdevice-aware power monitoring for a storage device. The flow diagram 700depicts example operations that may be performed by any suitable logicand/or components, including the components described throughout thisdisclosure (e.g., storage devices 120 of FIG. 1, storage device 200 ofFIG. 2, and/or storage device 500 of FIG. 5).

The flow diagram may begin at block 702 by accumulating the power usedfor each type of operation performed by the storage device. In someembodiments, for example, the storage device may include an N-energyaccumulator to track the power usage for each type of operation. TheN-energy accumulator may include, for example, a separate accumulatorfor each type of operation or work unit that may be performed by thestorage device. The corresponding accumulator for a particular type ofwork may then be incremented, for example, when that type of work isperformed by the storage device.

The flow diagram may then proceed to block 704 to determine the averagepower used by the storage device for a particular time interval. Theaverage power of the storage device may be calculated, for example,based on the accumulated energy values obtained in block 702.

The flow diagram may then proceed to block 706 to determine if theaverage power used by the storage device exceeds the target power forthe storage device. For example, the storage device may specify a targetpower that represents a power usage goal or threshold for the storagedevice. If it is determined in block 706 that the average power used bythe storage device does NOT exceed the target power, the flow diagrammay then proceed to block 710 to report power related information forthe storage device, as described below. If it is determined in block 706that the average power of the storage device does exceed the targetpower, the flow diagram may then proceed to block 708 to throttle thepower used by the storage device in order to achieve the target power.For example, the storage device may perform a real-time calibration oradjustment of the size of the power credit pool.

The flow diagram may then proceed to block 710 to report power relatedinformation for the storage device. For example, power usageinformation, statistics, and/or events may be reported to a hostcomputing system and/or a user.

At this point, the flow diagram may be complete. In some embodiments,however, the flow diagram may restart and/or certain blocks may berepeated. For example, in some embodiments, the flow diagram may restartat block 702 to continue monitoring, reporting, and/or throttling thepower used by the storage device.

The flow diagram described in FIG. 7 is merely representative ofoperations that may occur in particular embodiments. In otherembodiments, additional operations may be performed and/or certainoperations may be omitted. Various embodiments of the present disclosurecontemplate any suitable mechanisms for accomplishing the functionsdescribed herein. Some of the operations illustrated in the flow diagramof FIG. 7 may be repeated, combined, modified, and/or deleted whereappropriate. Additionally, operations may be performed in any suitableorder without departing from the scope of particular embodiments.

The functionality described throughout this disclosure may berepresented or implemented in various forms. For example, the design ofa product or component may go through various stages (e.g., fromcreation to simulation to fabrication) and may be represented in variousforms. First, as is useful in simulations, hardware may be representedusing a hardware description language (HDL) or another functionaldescription language. Additionally, a circuit level model with logicand/or transistor gates may be produced at some stages of the designprocess. Furthermore, most designs, at some stage, reach a level of datarepresenting the physical placement of various devices in the hardwaremodel. In the case where conventional semiconductor fabricationtechniques are used, the data representing the hardware model may be thedata specifying the presence or absence of various features on differentmask layers for masks used to produce the integrated circuit. In someimplementations, such data may be stored in a database file format suchas Graphic Data System II (GDS II), Open Artwork System InterchangeStandard (OASIS), or similar format.

In some implementations, software-based models of hardware, and HDL andother functional description language objects, can include registertransfer language (RTL) files, among other examples. Such objects can bemachine-parsable, such that a design tool can accept the HDL object (ormodel), parse the HDL object for attributes of the described hardware,and determine a physical circuit and/or on-chip layout from the object.The output of the design tool can be used to manufacture the physicaldevice. For instance, a design tool can determine configurations ofvarious hardware and/or firmware elements from the HDL object, such asbus widths, registers (including sizes and types), memory blocks,physical link paths, fabric topologies, among other attributes thatwould be implemented in order to realize the system modeled in the HDLobject. Design tools can include tools for determining the topology andfabric configurations of systems on a chip (SoC) and other hardwaredevices. In some instances, the HDL object can be used as the basis fordeveloping models and design files that can be used by manufacturingequipment to manufacture the described hardware. Indeed, an HDL objectitself can be provided as an input to manufacturing system software tocause the described hardware.

In any representation of the design, the associated data used torepresent the design may be stored in any form of a machine readablemedium. A memory or a magnetic or optical storage such as a disc may bethe machine readable medium to store information transmitted via opticalor electrical wave modulated or otherwise generated to transmit suchinformation. When an electrical carrier wave indicating or carrying thecode or design is transmitted, to the extent that copying, buffering, orre-transmission of the electrical signal is performed, a new copy ismade. Thus, a communication provider or a network provider may store ona tangible, machine-readable medium, at least temporarily, an article,such as information encoded into a carrier wave, embodying techniquesdescribed by the present disclosure.

As used herein, a module, component, controller, device, and/or enginemay refer to any combination of hardware, software, firmware, and/orother logic. As an example, a module may include hardware (e.g., amicrocontroller or application specific integrated circuit (ASIC))associated with a non-transitory medium to store code adapted to beexecuted by the hardware. Therefore, in some embodiments, modules andthe other terms identified above may refer to hardware that isspecifically configured to recognize and/or execute code held on anon-transitory medium. Furthermore, in other embodiments, modules andthe other terms identified above may refer to the non-transitory mediumand associated code that is specifically adapted to be executed by thehardware to perform certain operations. In addition, modules and theother terms identified above may refer to a combination of hardware(e.g., a microcontroller or ASIC), non-transitory mediums, and code. Theboundaries of modules (and the other terms identified above) often varyand potentially overlap, even though they may be illustrated as beingseparate. For example, a first and a second module may share hardware,software, firmware, or a combination thereof, while potentiallyretaining some independent hardware, software, or firmware.

Logic may be used to implement any of the functionality of the variouscomponents, such as CPU 102, processor 108, core 114, I/O controller110, CPU memory controller 112, main memory 104, storage device 120,data storage 122, storage controller 124, power controller 126, or othercomponents described herein. “Logic” may refer to hardware, firmware,software and/or combinations of each to perform one or more functions.In various embodiments, logic may include a microprocessor or otherprocessing element operable to execute software instructions, discretelogic such as an application specific integrated circuit (ASIC), aprogrammed logic device such as a field programmable gate array (FPGA),a storage device containing instructions, combinations of logic devices(e.g., as would be found on a printed circuit board), or other suitablehardware and/or software. Logic may include one or more gates or othercircuit components. In some embodiments, logic may also be fullyembodied as software. Software may be embodied as a software package,code, instructions, instruction sets and/or data recorded onnon-transitory computer readable storage medium. Firmware may beembodied as code, instructions or instruction sets and/or data that arehard-coded (e.g., nonvolatile) in storage devices.

Use of the phrase “to” or “configured to,” in one embodiment, refers toarranging, putting together, manufacturing, offering to sell, importingand/or designing an apparatus, hardware, logic, or element to perform adesignated or determined task. In this example, an apparatus or elementthereof that is not operating is still “configured to” perform adesignated task if it is designed, coupled, and/or interconnected toperform the designated task. As a purely illustrative example, a logicgate may provide an output of 0 or 1 during operation. However, a logicgate that is “configured to” provide a signal to enable or disable aclock, for example, does not include every potential logic gate that mayprovide an output of 0 or 1. Instead, the logic gate “configured to”enable or disable the clock is one that is configured and/or coupled insome manner such that its 0 or 1 output is used to enable or disable theclock. Note once again that use of the term “configured to” does notrequire operation, but instead focuses on the latent state of acomponent (e.g., an apparatus, hardware, software, module, and/or otherelement), such that the component is designed to perform a particulartask when the component is operating.

Furthermore, use of the phrases “capable of/to,” and or “operable to,”in one embodiment, refers to some apparatus, logic, hardware, and/orelement designed to enable use of the apparatus, logic, hardware, and/orelement in a specified manner. Note that, as above, use of “to,”“capable to,” or “operable to,” in one embodiment, refers to the latentstate of an apparatus, logic, hardware, and/or element, where theapparatus, logic, hardware, and/or element is not operating but isdesigned to enable use of an apparatus in a specified manner.

A value, as used herein, includes any known representation of a number,a state, a logical state, or a binary logical state. Often, the use oflogic levels, logic values, or logical values is also referred to as 1'sand 0's, which simply represent binary logic states. For example, a 1refers to a high logic level and 0 refers to a low logic level. In oneembodiment, a storage cell, such as a transistor or flash cell, may becapable of holding a single logical value or multiple logical values.However, other representations of values in computer systems have beenused. For example, the decimal number ten may also be represented as abinary value of 1010 and a hexadecimal letter A. Therefore, a valueincludes any representation of information capable of being held in acomputer system.

Moreover, states may be represented by values or portions of values. Asan example, a first value, such as a logical one, may represent adefault or initial state, while a second value, such as a logical zero,may represent a non-default state. In addition, the terms reset and set,in one embodiment, refer to a default and an updated value or state,respectively. For example, a default value potentially includes a highlogical value (i.e., reset), while an updated value potentially includesa low logical value (i.e., set). Note that any combination of values maybe utilized to represent any number of states.

The embodiments of methods, hardware, software, firmware or code setforth above may be implemented via instructions or code stored on amachine-accessible, machine readable, computer accessible, or computerreadable medium which are executable by a processing element. Anon-transitory machine-accessible/readable medium includes any mechanismthat provides (i.e., stores and/or transmits) information in a formreadable by a machine, such as a computer or electronic system. Forexample, a non-transitory machine-accessible medium includes:random-access memory (RAM), such as static RAM (SRAM) or dynamic RAM(DRAM); ROM; magnetic or optical storage medium; flash storage devices;electrical storage devices; optical storage devices; acoustical storagedevices; and other forms of storage devices for holding informationreceived from transitory (propagated) signals (e.g., carrier waves,infrared signals, digital signals).

Instructions used to program logic to perform embodiments of thedisclosure may be stored within a memory in the system, such as DRAM,cache, flash memory, or other storage. Furthermore, the instructions canbe distributed via a network or by way of other computer readable media.Thus a machine-readable medium may include any mechanism for storing ortransmitting information in a form readable by a machine (e.g., acomputer), but is not limited to, floppy diskettes, optical disks,Compact Disc, Read-Only Memory (CD-ROMs), magneto-optical disks,Read-Only Memory (ROMs), Random Access Memory (RAM), ErasableProgrammable Read-Only Memory (EPROM), Electrically ErasableProgrammable Read-Only Memory (EEPROM), magnetic or optical cards, flashmemory, or a tangible, machine-readable storage used in the transmissionof information over the Internet via electrical, optical, acoustical orother forms of propagated signals (e.g., carrier waves, infraredsignals, digital signals). Accordingly, a machine-readable medium mayinclude any type of tangible medium suitable for storing or transmittingelectronic instructions or information in a form readable by a machine(e.g., a computer).

The following examples pertain to embodiments described throughout thisdisclosure.

One or more embodiments may include an apparatus comprising: anon-volatile data storage; a storage controller to: receive a commandfor the data storage, wherein the command comprises a plurality ofstages; and dynamically allocate power for the plurality of stages ofthe command, wherein power for a first stage of the command is allocatedfirst, and power for each remaining stage of the command is allocatedafter a preceding stage is performed.

In one example embodiment of an apparatus, the storage controllerconfigured to dynamically allocate power for the plurality of stages ofthe command is further configured to: allocate power for the first stageof the command; initiate performance of the first stage of the command;allocate power for a second stage of the command; initiate performanceof the second stage of the command; and release power allocated for thecommand.

In one example embodiment of an apparatus, the apparatus furthercomprises: a first interface to request a power allocation for the firststage of the command; a second interface to request a power allocationfor the second stage of the command; and a third interface to request apower release for the command.

In one example embodiment of an apparatus, the storage controllerconfigured to allocate power for the second stage of the command isfurther configured to adjust the power allocated for the first stage ofthe command.

In one example embodiment of an apparatus, power for the first stage ofthe command is allocated after allocating power for a second stage ofone or more pending commands.

In one example embodiment of an apparatus, the command comprises astorage access operation and a data processing operation.

In one example embodiment of an apparatus, the storage controller isfurther configured to: determine that the first stage of the command iscomplete; determine that a power allocation is pending for a secondstage of a different command; release the power allocated for the firststage of the command; and allocate power for the second stage of thedifferent command.

In one example embodiment of an apparatus, the storage controller isfurther configured to monitor power usage for each type of operationperformed by the apparatus.

In one example embodiment of an apparatus, the storage controller isfurther configured to: accumulate the power usage for each type ofoperation performed by the apparatus; determine, based on theaccumulated power usage, an average power used by the apparatus; andthrottle power usage when the average power exceeds a target powerusage.

In one example embodiment of an apparatus, the accumulated power usagefor each type of operation performed by the apparatus comprises powerusage for storage access operations, data processing operations, andsystem event operations.

In one example embodiment of an apparatus, the storage controller isfurther configured to report the accumulated power usage for each typeof operation performed by the apparatus.

One or more embodiments may include a method comprising: receiving acommand for a storage device, wherein the command comprises a pluralityof stages; and dynamically allocating power for the plurality of stagesof the command, wherein power for a first stage of the command isallocated first, and power for each remaining stage of the command isallocated after a preceding stage is performed.

In one example embodiment of a method, dynamically allocating power forthe plurality of stages of the command comprises: allocating power forthe first stage of the command; performing the first stage of thecommand; allocating power for a second stage of the command; performingthe second stage of the command; and releasing power allocated for thecommand.

In one example embodiment of a method, the method further comprises:requesting, using a first interface, a power allocation for the firststage of the command; requesting, using a second interface, a powerallocation for the second stage of the command; and requesting, using athird interface, a power release for the command.

In one example embodiment of a method, allocating power for the secondstage of the command comprises adjusting the power allocated for thefirst stage of the command.

In one example embodiment of a method, the method further comprises:determining that the first stage of the command is complete; determiningthat a power allocation is pending for a second stage of a differentcommand; releasing the power allocated for the first stage of thecommand; and allocating power for the second stage of the differentcommand.

In one example embodiment of a method, the method further comprisesmonitoring power usage for each type of operation performed by thestorage device.

In one example embodiment of a method, the method further comprises:accumulating the power usage for each type of operation performed by thestorage device; determining, based on the accumulated power usage, anaverage power used by the storage device; and throttling power usagewhen the average power exceeds a target power usage.

One or more embodiments may include a system comprising: a processor; astorage device comprising: a non-volatile data storage; a storagecontroller to: receive a command for the storage device, wherein thecommand comprises a plurality of stages; and dynamically allocate powerfor the plurality of stages of the command, wherein power for a firststage of the command is allocated first, and power for each remainingstage of the command is allocated after a preceding stage is performed.

In one example embodiment of a system, the system further comprises: adisplay communicatively coupled to the processor; a network interfacecommunicatively coupled to the processor; or a battery coupled to theprocessor.

Reference throughout this specification to “one embodiment” or “anembodiment” means that a particular feature, structure, orcharacteristic described in connection with the embodiment is includedin at least one embodiment of the present disclosure. Thus, theappearances of the phrases “in one embodiment” or “in an embodiment” invarious places throughout this specification are not necessarily allreferring to the same embodiment. Furthermore, the particular features,structures, or characteristics may be combined in any suitable manner inone or more embodiments.

In the foregoing specification, a detailed description has been givenwith reference to specific exemplary embodiments. It will, however, beevident that various modifications and changes may be made theretowithout departing from the broader spirit and scope of the disclosure asset forth in the appended claims. The specification and drawings are,accordingly, to be regarded in an illustrative sense rather than arestrictive sense. Furthermore, the foregoing use of embodiment andother exemplarily language does not necessarily refer to the sameembodiment or the same example, but may refer to different and distinctembodiments, as well as potentially the same embodiment.

What is claimed is:
 1. An apparatus comprising: a non-volatile datastorage; a storage controller to: receive a command for the datastorage, wherein the command comprises a plurality of stages; anddynamically allocate power for the plurality of stages of the command,wherein power for a first stage of the command is allocated first, andpower for each remaining stage of the command is allocated after apreceding stage is performed.
 2. The apparatus of claim 1, wherein thestorage controller configured to dynamically allocate power for theplurality of stages of the command is further configured to: allocatepower for the first stage of the command; initiate performance of thefirst stage of the command; allocate power for a second stage of thecommand; initiate performance of the second stage of the command; andrelease power allocated for the command.
 3. The apparatus of claim 2,further comprising: a first interface to request a power allocation forthe first stage of the command; a second interface to request a powerallocation for the second stage of the command; and a third interface torequest a power release for the command.
 4. The apparatus of claim 2,wherein the storage controller configured to allocate power for thesecond stage of the command is further configured to adjust the powerallocated for the first stage of the command.
 5. The apparatus of claim1, wherein power for the first stage of the command is allocated afterallocating power for a second stage of one or more pending commands. 6.The apparatus of claim 1, wherein the command comprises a storage accessoperation and a data processing operation.
 7. The apparatus of claim 1,wherein the storage controller is further configured to: determine thatthe first stage of the command is complete; determine that a powerallocation is pending for a second stage of a different command; releasethe power allocated for the first stage of the command; and allocatepower for the second stage of the different command.
 8. The apparatus ofclaim 1, wherein the storage controller is further configured to monitorpower usage for each type of operation performed by the apparatus. 9.The apparatus of claim 8, wherein the storage controller is furtherconfigured to: accumulate the power usage for each type of operationperformed by the apparatus; determine, based on the accumulated powerusage, an average power used by the apparatus; and throttle power usagewhen the average power exceeds a target power usage.
 10. The apparatusof claim 9, wherein the accumulated power usage for each type ofoperation performed by the apparatus comprises power usage for storageaccess operations, data processing operations, and system eventoperations.
 11. The apparatus of claim 9, wherein the storage controlleris further configured to report the accumulated power usage for eachtype of operation performed by the apparatus.
 12. A method comprising:receiving a command for a storage device, wherein the command comprisesa plurality of stages; and dynamically allocating power for theplurality of stages of the command, wherein power for a first stage ofthe command is allocated first, and power for each remaining stage ofthe command is allocated after a preceding stage is performed.
 13. Themethod of claim 12, wherein dynamically allocating power for theplurality of stages of the command comprises: allocating power for thefirst stage of the command; performing the first stage of the command;allocating power for a second stage of the command; performing thesecond stage of the command; and releasing power allocated for thecommand.
 14. The method of claim 13, further comprising: requesting,using a first interface, a power allocation for the first stage of thecommand; requesting, using a second interface, a power allocation forthe second stage of the command; and requesting, using a thirdinterface, a power release for the command.
 15. The method of claim 13,wherein allocating power for the second stage of the command comprisesadjusting the power allocated for the first stage of the command. 16.The method of claim 12, further comprising: determining that the firststage of the command is complete; determining that a power allocation ispending for a second stage of a different command; releasing the powerallocated for the first stage of the command; and allocating power forthe second stage of the different command.
 17. The method of claim 12,further comprising monitoring power usage for each type of operationperformed by the storage device.
 18. The method of claim 17, furthercomprising: accumulating the power usage for each type of operationperformed by the storage device; determining, based on the accumulatedpower usage, an average power used by the storage device; and throttlingpower usage when the average power exceeds a target power usage.
 19. Asystem comprising: a processor; a storage device comprising: anon-volatile data storage; a storage controller to: receive a commandfor the storage device, wherein the command comprises a plurality ofstages; and dynamically allocate power for the plurality of stages ofthe command, wherein power for a first stage of the command is allocatedfirst, and power for each remaining stage of the command is allocatedafter a preceding stage is performed.
 20. The system of claim 19,further comprising: a display communicatively coupled to the processor;a network interface communicatively coupled to the processor; or abattery coupled to the processor.